im running a carter electric pump and a mallory 3 port regulator on my 383. The pump says it good up to 8 psi but for some reason i cannot get anymore than 4.5 psi according to my inline guage. After i drive it or let it idle for 5-10 min. the pressure drops down to around 0-1 psi. The screw is as far down on the regulator as it will go and it max out at 4.5 when first started. I checked the fuel filter and it was in good shape. The electric intank pump has been removed so its free flowing, whats the problem here? I took the fittings off the regulator and cleaned some tape out of it but it didnt seem to make a difference. I dont believe it is vapor lock because my pump is far away from my exhaust and any heat source. Anybody have any ideas?

 

anybody?? Ran a hose from the fuel pump to the regulator outside the car and the pressure still drops to around 3 after idleing for 5-10 min. I guess that eliminates vapor lock. Anybody else have any suggestions? Do these regulators go bad often, its new so i hope not!

 

could you have damaged the regulator by bottoming the adjustment screw?

 

You arent supposed to bottom out the adjustment screw?

 

try screwing it the other way.. i dont remember how my holley regulator works but i screwed it in one way and pressure went opposite of what i wanted.. keep playing around with it..

 

Why do you need the regulator?
I would look at the inlet (feed) side of the fuel pump for a soft or kinked collapsed fuel line (heat) or maybe junk in the pump. Most of the carter electric pumps do not require a regulator. Which model pump do you have
?

 

i see no problems with the fuel line. The pump is a carter P4600HP. When i start the car up cold, the pressure jumps up to 8psi and slowly bleeds down as the car warms up. I took the regulator out and ran a straight hose and it did the same thing. Hooked a volt meter up to the pump and it read 11.9x. Anybody have anymore ideas?

 

I switched to a holley blue fuel pump and set the fuel pressure at 7psi and took it for a 10 min drive, came back and it was still at 7 psi. I let the car idle for another 5-10 min. and the pressure slowly dropped down to 4.8-5 psi. Is this normal?

 

are you pumping through a inline filter after the pump?

 

yes it is after the pump.

 

clean it or replace it and i bet your pressure problem goes away

 

Its new! I took it off and checked the filter and it was as clean as it gets.

 

okay is the filter made to be pumped through or is a drawthrough?

 

He is getting a voltage drop. When you're on the gas, voltage is good, around 13V, maybe a little more. Stop the car and let it idle, fans come on, voltage drops to something like 10V. Thinking this may be because of underdrive pulleys, not sure yet. I know on my firebird, fans on, my voltage is still around 13V. Like he said with the Holley pump, starts at 7, after idling for a while (or come back from a drive and idle it) then pressure is around 4-5. With the carter, pressure starts off ok, drops to almost nothing. Seems like even 9 or 10V should be enough to push even a few psi?

If I have him hold the gas so the voltage rises again to 13V, the pressure doesn't seem to rise again, stays around 4-5psi with the Holley pump, where initially it was 7. Dunno.

 

where are you taking the pressure readings?

 

right before the duel feed into the carb (after the regulator)

 

okay well you should test the pressure before the regulator if possible or both at the same time would be great help point the finger in the right direction at least

if both pumps are doing it, it probably isnt the pump.

what kind of a pickup are you running in the tank

 

It's a straight tube (rubber extension is how he did it I think, after removing the stocker FI pump).